Shackamaxon Dam Reservoir Report

Last Updated: December 7, 2025

Shackamaxon Dam, located in Union, New Jersey, along Lambert's Run, serves primarily for irrigation purposes.


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Summary

This private earth dam stands at a height of 24.1 feet and has a storage capacity of 53 acre-feet, providing vital water resources for agricultural needs in the area. The dam has a fair condition assessment and a high hazard potential, indicating the importance of regular inspections and maintenance to ensure its safety and stability.

Managed by the New Jersey Department of Environmental Protection, Shackamaxon Dam plays a crucial role in water resource management in the region. With a drainage area of 2.5 square miles and a maximum discharge capacity of 1290 cubic feet per second, the dam helps regulate water flow and prevent flooding downstream. Although the dam's last inspection in March 2019 deemed it to be in fair condition, ongoing monitoring and risk assessment measures are essential to mitigate any potential hazards and safeguard the surrounding community.

As a key infrastructure for water supply and management, Shackamaxon Dam underscores the significance of sustainable water resource practices and climate resilience. With its strategic location in Scotch Plains Township and its vital role in supporting irrigation activities, the dam serves as a critical asset for ensuring water security and environmental sustainability in the region. Continued collaboration among relevant agencies and stakeholders is essential to maintain the dam's integrity and enhance its resilience in the face of changing climate conditions and water resource challenges.

Dam Length

275

Dam Height

24.1

River Or Stream

Lambert's Run

Primary Dam Type

Earth

Surface Area

11

Drainage Area

2.5

Nid Storage

53

Hazard Potential

High

Nid Height

24
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.

Hazard Potential Classification

High
Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.